Social Tango in Buenos Aires is a dance around the perimeter of the room. It is RECTANGULAR, rather than circular. (Performance tango is the opposite, requiring you to fill the interior space of the stage). Crowded conditions are best handled by setting up lanes. The outer perimeter of the floor is the first lane. When that gets too full, use the 2nd lane, and then the 3rd. The outer lane tends to be safer, as you have potential collisions only from the inside.